1. Field
One embodiment of the invention relates to a head used in a disk device such as a magnetic disk device, a head suspension assembly provided with the head, and a disk device provided with the head suspension assembly.
2. Description of the Related Art
A disk device, e.g., a magnetic disk device, includes a magnetic disk, spindle motor, magnetic head, and carriage assembly. The magnetic disk is arranged in a case. The spindle motor supports and rotates the disk. The magnetic head writes and reads information to and from the disk. The carriage assembly supports the magnetic head for movement with respect to the magnetic disk. The carriage assembly includes a rotatably supported arm and a suspension extending from the arm. The magnetic head is supported on an extended end of the suspension. The head includes a slider attached to the suspension and a head portion on the slider. The head portion is constructed including a reproducing element for reading and a recording element for writing.
The slider has a facing surface (air bearing surface: ABS) that is opposed to a recording surface of the magnetic disk. A predetermined head load directed to a magnetic recording layer of the disk is applied to the slider by the suspension. When the magnetic disk device operates, an airflow is generated between the disk in rotation and the slider. Based on the principle of aerodynamic lubrication, a force (positive pressure) to fly the slider above the recording surface of the disk acts on the facing surface of the slider. By balancing this flying force with the head load, the slider is flown with a given gap above the recording surface of the disk. There is provided a disk device in which a negative-pressure cavity or a dynamic pressure generating groove is formed near the center of the facing surface of the slider in order to prevent fluctuations of the flying height.
In a conventional magnetic disk, moreover, a lubricant is spread thinly on the disk surface to reduce its abrasion by contact with a magnetic head. Although most of the lubricant adheres to the disk surface, a small portion may sometimes leave the disk surface and adhere to a facing surface of a slider. If the lubricant adheres to the slider, the adhesion increases gradually. If this adhesion exceeds a certain level, the lubricant drops from the slider onto the disk surface and forms a protuberance that adheres to the disk surface. If this protuberance of the lubricant is formed on the disk surface, the magnetic head unduly floats above the disk surface as it passes over the protuberance, thereby incurring a so-called high-fly write state. In some cases, therefore, the magnetic head may fail to accurately write and read information to and from the disk surface.
There is provided a device in which a plurality of noncontinuous portions are arranged on a facing surface of a slider to form standing-air regions that prevent a lubricant from adhering to the surface of a slider by a surface tension between the slider surface and the disk surface (e.g., Japanese Publication No. 2001-503903).
In the magnetic disk device, most of air that flows between the disk surface and the slider forms regular flows that run from the air inlet end side of the slider to the outlet end side. However, some of the air forms backflows that run reversely between the slider and the disk surface after having once run out of the slider.
If such backflows occurs, the lubricant that is lifted above the disk surface flows toward and adheres to the facing surface of the slider. If the adhesion of the lubricant gradually increases, the lubricant finally drops on the disk surface and forms a protuberance that adheres to the disk surface. If this protuberance of the lubricant is formed on the disk surface, as mentioned before, the magnetic head unduly floats above the disk surface, thereby incurring the so-called high-fly write.
Although the adhesion of the lubricant that is attributable to the surface tension can be reduced in the conventional magnetic disk device described above, it is difficult to suppress the adhesion of the lubricant that is caused by the backflows.